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<a href="cong__ctl__util_8cpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#include &quot;<a class="code" href="cong__ctl__util_8hpp.html">flow/net_flow/detail/cong_ctl/cong_ctl_util.hpp</a>&quot;</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span><span class="preprocessor">#include &lt;limits&gt;</span></div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span> </div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceflow_1_1net__flow.html">flow::net_flow</a></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span>{</div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="comment">// Static initializations.</span></div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span> </div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="comment">/* By setting this to infinity, we disable any limit on per-ack-group CWND incrementing.</span></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span><span class="comment"> * For reasons why see on_acks(). */</span></div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="keyword">const</span> <span class="keywordtype">size_t</span> <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#ad5141d276b63528195d360f537cd4882">Congestion_control_classic_data::S_MAX_SLOW_START_CWND_INCREMENT_BLOCKS</a></div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span>  = std::numeric_limits&lt;size_t&gt;::max();</div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span> </div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment">// Implementations.</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span> </div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a537fe6cb424b4e2591cc4673ed9ec8a1">   33</a></span><a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a537fe6cb424b4e2591cc4673ed9ec8a1">Congestion_control_classic_data::Congestion_control_classic_data</a>(<a class="code hl_class" href="classflow_1_1log_1_1Logger.html">log::Logger</a>* logger_ptr,</div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span>                                                                 <a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> sock) :</div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span>  log::Log_context(logger_ptr, <a class="code hl_enumeration" href="namespaceflow.html#a3938730ab4b89daf13d027a5f620e7ce">Flow_log_component</a>::S_NET_FLOW_CC),</div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span>  m_sock(sock),</div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span>  <span class="comment">// Initialize CWND in a standard way, or use the option&#39;s overriding value if provided.</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span>  m_cong_wnd_bytes(sock-&gt;max_block_size() * <span class="comment">// Initial CWND a multiple of max-block-size always.</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span>                   ((sock-&gt;opt(sock-&gt;m_opts.m_st_cong_ctl_init_cong_wnd_blocks) == 0)</div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span>                      ? ((sock-&gt;max_block_size() &gt; 2190) <span class="comment">// Not option-specified; use RFC 5681.</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span>                           ? 2 <span class="comment">// In (2190, ...).</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span>                           : ((sock-&gt;max_block_size() &gt; 1095)</div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span>                                ? 3  <span class="comment">// In (1095, 2190].</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span>                                : 4)) <span class="comment">// In [1, 1095].</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span>                      : sock-&gt;opt(sock-&gt;m_opts.m_st_cong_ctl_init_cong_wnd_blocks))), <span class="comment">// Option-specified.</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span>  m_init_cong_wnd_bytes(m_cong_wnd_bytes),</div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span>  <span class="comment">// SSTHRESH set to infinity as recommended by RFC 5681-3.1 and others.  Will be set to finite value on drop.</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span>  m_slow_start_thresh_bytes(std::numeric_limits&lt;size_t&gt;::max()),</div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span>  m_acked_bytes_since_window_update(0)</div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span>{</div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span>  <span class="comment">/* Initial CWND is chosen above according to RFC 5681-3.1 (for TCP) (unless it&#39;s overridden with</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment">   * m_st_init_cond_wnd_blocks option).</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment">   *</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment">   * I&#39;m blindly following the RFC here.  Whatever reasoning led to the above formula is probably</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment">   * about right for us too; IP+UDP+Flow overhead should not be too much different from IP+TCP</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment">   * overhead.  Anyway, the initial CWND is just a safe guess and will change quickly regardless. */</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span> </div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span>  <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a092ddd8d1f700b426a5f9e0184af004f">log_state</a>(<span class="stringliteral">&quot;construction&quot;</span>);</div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span>}</div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span> </div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#adbda0ed3747b1eea62f4d790c37dbe46">   61</a></span><span class="keywordtype">size_t</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#adbda0ed3747b1eea62f4d790c37dbe46">Congestion_control_classic_data::congestion_window_bytes</a>()<span class="keyword"> const</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span>  <span class="keywordflow">return</span> <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a>;</div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span>}</div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span> </div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#acaa476e1821e7ed1344de8c5bfc0c9a7">   66</a></span><span class="keywordtype">size_t</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#acaa476e1821e7ed1344de8c5bfc0c9a7">Congestion_control_classic_data::init_congestion_window_bytes</a>()<span class="keyword"> const</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span>  <span class="keywordflow">return</span> <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7c792d850821c8a7c711204db867089b">m_init_cong_wnd_bytes</a>;</div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span>}</div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span> </div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a1ca80ab86d6289af0f3b2bf123edd627">   71</a></span><span class="keywordtype">size_t</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a1ca80ab86d6289af0f3b2bf123edd627">Congestion_control_classic_data::slow_start_threshold_bytes</a>()<span class="keyword"> const</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span>  <span class="keywordflow">return</span> <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a239c6315ca562c4e782431879f39c74d">m_slow_start_thresh_bytes</a>;</div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span>}</div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span> </div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#ab3e34468efdf4d9e5b29eceb1fe84665">   76</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#ab3e34468efdf4d9e5b29eceb1fe84665">Congestion_control_classic_data::on_acks</a>(<span class="keywordtype">size_t</span> bytes)</div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span>{</div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span>  <span class="keyword">using </span>std::min;</div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span> </div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span>  <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a092ddd8d1f700b426a5f9e0184af004f">log_state</a>(<span class="stringliteral">&quot;ack-handling-before&quot;</span>);</div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span> </div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span>  <span class="keyword">const</span> <a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> sock = <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">socket</a>();</div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span> </div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span>  <span class="keywordflow">if</span> (<a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a9c6cac4d5409855f5e39f4411d787ad9">congestion_window_at_limit</a>())</div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span>  {</div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span>    <span class="comment">/* Once we&#39;ve maxed out CWND, some of the below calculations make no sense and wouldn&#39;t result</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment">     * in an increased CWND anyway.  If we are in slow start, this is nothing more than a little</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment">     * optimization.  If we are in congestion avoidance, then it&#39;s a bit more complex:</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment">     * m_acked_bytes_since_window_update state remains unchaged which may seem like it might have</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment">     * implications on when CWND is no longer at the limit in the future (does congestion avoidance</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment">     * resume as if nothing happened or what?).  HOWEVER, any change in CWND that would lower it</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment">     * will have to be done through congestion_event(), in which case</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="comment">     * m_acked_bytes_since_window_update will reset to zero, so what we do with</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="comment">     * m_acked_bytes_since_window_update at this point is immaterial.  Therefore it&#39;s safe to simply</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment">     * do nothing here. */</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span>    <a class="code hl_define" href="log_8hpp.html#affcf2e4c496ce3f42adf981669c623b8">FLOW_LOG_TRACE</a>(<span class="stringliteral">&quot;cong_ctl [&quot;</span> &lt;&lt; sock &lt;&lt; <span class="stringliteral">&quot;] update: cong_wnd already at limit.&quot;</span>);</div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span>  }</div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span>  <span class="keywordflow">else</span> <span class="keywordflow">if</span> (<a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#aecb03f208c177ec3cbce5242f19efee0">in_slow_start</a>())</div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span>  {</div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span>    <span class="comment">/* We perform slow start CWND increase based on classic Reno TCP (RFC 5681) with the Appropriate</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment">     * Byte Counting (ABC) modification (RFC 3465-2.2).  It says, simply, to increment CWND by the</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment">     * number of bytes acknowledged.  By the way, ABC is the reason I ultimately chose to store CWND</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment">     * in bytes, not max-blocks; implementing ABC with a multiples-of-max-block-size CWND is tricky.</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment">     * (Linux TCP does it.  The code is difficult to understand.)</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment">     *</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment">     * Well, there is one difficulty.  The RFC also says to increase CWND as above but capped by a</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment">     * maximum of L bytes, where L is 2 * max-block-size.</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment">     *</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment">     * The justification is: &quot;A very large L could potentially lead to large line-rate bursts of</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment">     * traffic in the face of a large amount of ACK loss or in the case when the receiver sends</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment">     * &#39;stretch ACKs&#39; (ACKs for more than the two full-sized segments allowed by the delayed ACK</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment">     * algorithm).&quot;  I don&#39;t know what the first part means, but let&#39;s deal with the second part.</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment">     * For now, let&#39;s say we know for a fact that the receiver&#39;s net_flow is the same as our net_flow.</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment">     * net_flow does not send stretch acknowledgments; it sends an ACK -- at the latest -- when it</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment">     * has 2 un-acked DATA segments ready to acknowledge.  If we assume good behavior (which for now</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment">     * we will), then &quot;stretch ACKs&quot; are not a concern.</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment">     *</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment">     * However, the main reason the limit of 2 makes no sense for us is the following.  The RFC,</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment">     * when describing how to increment CWND based on an ACK, is describing a slightly different</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment">     * situation than on_acks().  To illustrate the difference, suppose 10 segments happen to arrive</span></div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment">     * at the same time, each acknowledging a different data segment sent earlier (for this example,</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment">     * suppose each one acks one MSS).  The RFC describes what to do for *each* of them.  Therefore,</span></div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment">     * for each one CWND will increase by 1 MSS (for 10 MSS total).  Now imagine the equivalent</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span><span class="comment">     * situation in Flow protocol: 10 individual acknowledgments arrive at the same time (perhaps even in one</span></div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment">     * ACK, which can happen in high-bandwidth situations).  Based on the documented rule for</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment">     * calling on_acks(), it will be called ONCE, with bytes = 10 * max-block-size.  If we were to</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="comment">     * apply the limit of 2 we&#39;d only increase CWND by 2 * max-block-size -- 5x less than even the</span></div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment">     * RFC would recommend!  Therefore we should disregard the limit part of the RFC, as it doesn&#39;t</span></div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment">     * apply to us.  We are perhaps vulnerable to our equivalent of &quot;stretch ACKs&quot; if the other</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment">     * net_flow misbehaves, but let&#39;s not sweat it until it&#39;s a problem.</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment">     *</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment">     * ...That was difficult to explain in writing.  The bottom line is, I do allow for a limit</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment">     * S_MAX_SLOW_START_CWND_INCREMENT_BLOCKS a-la RFC but recommend that, at least for now, we set</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment">     * it to basically infinity, because the model the RFC assumes is not quite the model we use and</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment">     * would thus lead to far-too-slow CWND growth during slow start in a high-bandwidth situation</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment">     * like transfer over localhost.  I have seen that first-hand with the value set to 2. */</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span> </div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span>    <span class="keyword">const</span> <span class="keywordtype">size_t</span> limit = <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#ad5141d276b63528195d360f537cd4882">S_MAX_SLOW_START_CWND_INCREMENT_BLOCKS</a> * sock-&gt;max_block_size();</div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span>    <span class="keyword">const</span> <span class="keywordtype">size_t</span> increment_bytes = min(bytes, limit);</div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span> </div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span>    <a class="code hl_define" href="log_8hpp.html#affcf2e4c496ce3f42adf981669c623b8">FLOW_LOG_TRACE</a>(<span class="stringliteral">&quot;cong_ctl [&quot;</span> &lt;&lt; sock &lt;&lt; <span class="stringliteral">&quot;] update: [slow_start] cong_wnd incrementing &quot;</span></div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span>                   <span class="stringliteral">&quot;by [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(increment_bytes) &lt;&lt; <span class="stringliteral">&quot;]; &quot;</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span>                   <span class="stringliteral">&quot;acked [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(bytes) &lt;&lt; <span class="stringliteral">&quot;]; &quot;</span></div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span>                   <span class="stringliteral">&quot;max increment [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(limit) &lt;&lt; <span class="stringliteral">&quot;].&quot;</span>);</div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span> </div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span>    <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a> += increment_bytes;</div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span>    <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7b798f3211fd2214477355b95e2d10d2">clamp_congestion_window</a>(); <span class="comment">// If exceeded limit, bring it to the limit.</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span> </div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span>    <span class="comment">/* Take opportunity to ensure our arithmetic is working; this field should be zero outside of</span></div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span><span class="comment">     * congestion avoidance.  Thus if we just equalled or exceeded SSTRESH, thus entering</span></div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment">     * congestion avoidance, then this is a clean slate. */</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span>    assert(<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a217f407429d1cf215177e3f49f86b6d6">m_acked_bytes_since_window_update</a> == 0);</div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span>  }</div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span>  <span class="keywordflow">else</span> <span class="comment">// if (!in_slow_start())</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span>  {</div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span>    <span class="comment">/* In congestion avoidance, also follow classic Reno RFC 5681 with the ABC modification (RFC</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment">     * 3465-2.1).  For every CWND bytes acked in a row, increase CWND by a block, and then decrease</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="comment">     * the byte tally by the pre-increase CWND.  This causes a linear-ish growth in CWND while in</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment">     * congestion avoidance.  We add the feature to make the increment N * block, where N is configurable</span></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment">     * (the growth is still linear).</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span><span class="comment">     *</span></div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span><span class="comment">     * As always there is a caveat that prevents the below code from literally following the</span></div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment">     * algorithm from RFC.  More precisely, we follow the RFC algorithm and, if after that</span></div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span><span class="comment">     * bytes_acked &gt;= CWND still, we reapply the RFC algorithm.  We repeat until bytes_acked &lt; CWND.</span></div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span><span class="comment">     *</span></div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span><span class="comment">     * How can bytes_acked match or exceed CWND after applying the RFC algorithm once?  I believe</span></div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="comment">     * it&#39;s impossible assuming the expected handling of Dropped packets in Node.  However I</span></div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment">     * cannot/don&#39;t want to prove this to myself, especially with edge cases with a very low CWND</span></div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment">     * yet somehow a quite large ack group (large &quot;bytes&quot; arg value).  Therefore, to be safe, I</span></div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment">     * added the handling for this case. */</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span> </div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span>    <span class="comment">// Add the newly acked bytes to the tally.</span></div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span>    <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a217f407429d1cf215177e3f49f86b6d6">m_acked_bytes_since_window_update</a> += bytes;</div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span> </div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span>    <span class="comment">/* Increase CWND if that has put us over the top.  Repeat if we&#39;re still over the top after</span></div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span><span class="comment">     * increasing CWND and accordingly decreasing the tally.  In the usual case</span></div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span><span class="comment">     * this loop will execute once, reducing the algorithm to the one in the RFC. */</span></div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span>    <span class="keywordtype">bool</span> cwnd_changed = <span class="keyword">false</span>;</div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span>    <span class="keywordflow">while</span> ((<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a217f407429d1cf215177e3f49f86b6d6">m_acked_bytes_since_window_update</a> &gt;= <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a>)</div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span>           <span class="comment">// Can&#39;t be true in 1st iteration (eliminated in if () above) but can become true after 1st iteration:</span></div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span>           &amp;&amp; (!<a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a9c6cac4d5409855f5e39f4411d787ad9">congestion_window_at_limit</a>()))</div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span>    {</div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span>      <span class="comment">// Have a full CWND&#39;s worth of acked bytes; increase CWND.</span></div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span> </div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span>      <span class="keywordflow">if</span> (!cwnd_changed)</div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span>      {</div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span>        cwnd_changed = <span class="keyword">true</span>;</div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span>      }</div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span>      <span class="keywordflow">else</span> <span class="comment">// (already is true)</span></div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span>      {</div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span>        <span class="comment">// This should be rare or impossible, but not an error.  An INFO is in order.</span></div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span>        <a class="code hl_define" href="log_8hpp.html#a325fdd4b5cf0be49b37d3b7b7c29070d">FLOW_LOG_INFO</a>(<span class="stringliteral">&quot;cong_ctl [&quot;</span> &lt;&lt; sock &lt;&lt; <span class="stringliteral">&quot;] info: [cong_avoid] acknowledgment group brings tally to more &quot;</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span>                      <span class="stringliteral">&quot;than one congestion window -- thought to be rare or impossible.&quot;</span>);</div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span>      }</div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span> </div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span>      <span class="comment">/* Extend RFC 5681: in the RFC, this is simply 1.  If they specify special value 0, use that value.</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span><span class="comment">       * Otherwise use the value they give. */</span></div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno">  198</span>      <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> increment_blocks = sock-&gt;opt(sock-&gt;m_opts.m_st_cong_ctl_cong_avoidance_increment_blocks);</div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span>      <span class="keywordflow">if</span> (increment_blocks == 0)</div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span>      {</div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno">  201</span>        increment_blocks = 1;</div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno">  202</span>      }</div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span>      <span class="keyword">const</span> <span class="keywordtype">size_t</span> increment_bytes = increment_blocks * sock-&gt;max_block_size();</div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span> </div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span>      <a class="code hl_define" href="log_8hpp.html#affcf2e4c496ce3f42adf981669c623b8">FLOW_LOG_TRACE</a>(<span class="stringliteral">&quot;cong_ctl [&quot;</span> &lt;&lt; sock &lt;&lt; <span class="stringliteral">&quot;] update: [cong_avoid] cong_wnd incrementing &quot;</span></div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span>                     <span class="stringliteral">&quot;by [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(increment_bytes) &lt;&lt; <span class="stringliteral">&quot;]; &quot;</span></div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span>                     <span class="stringliteral">&quot;acked [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(bytes) &lt;&lt; <span class="stringliteral">&quot;].&quot;</span>);</div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno">  208</span> </div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span>      <span class="comment">// &quot;Convert&quot; the CWND&#39;s worth of acked bytes into N-block increase of CWND (as in RFC, though there N=1).</span></div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span> </div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span>      <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a217f407429d1cf215177e3f49f86b6d6">m_acked_bytes_since_window_update</a> -= <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a>;</div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span> </div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span>      <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a> += increment_bytes;</div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span>      <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7b798f3211fd2214477355b95e2d10d2">clamp_congestion_window</a>(); <span class="comment">// If exceeded limit, bring it to the limit.  (while() loop will exit in that case.)</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span>    } <span class="comment">// while ((bytes_acked &gt;= CWND) &amp;&amp; (CWND &lt; max CWND)</span></div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno">  216</span> </div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span>    <span class="keywordflow">if</span> (!cwnd_changed)</div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno">  218</span>    {</div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno">  219</span>      <span class="comment">// Don&#39;t have a full CWND&#39;s worth of acked bytes yet; leave CWND alone.</span></div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span>      <a class="code hl_define" href="log_8hpp.html#affcf2e4c496ce3f42adf981669c623b8">FLOW_LOG_TRACE</a>(<span class="stringliteral">&quot;cong_ctl [&quot;</span> &lt;&lt; sock &lt;&lt; <span class="stringliteral">&quot;] update: [cong_avoid] cong_wnd not yet incrementing; &quot;</span></div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span>                     <span class="stringliteral">&quot;acked [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(bytes) &lt;&lt; <span class="stringliteral">&quot;].&quot;</span>);</div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span>    }</div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno">  223</span>  } <span class="comment">// else if (!in_slow_start())</span></div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span> </div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span>  <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a092ddd8d1f700b426a5f9e0184af004f">log_state</a>(<span class="stringliteral">&quot;ack-handling-after&quot;</span>);</div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span>} <span class="comment">// void Congestion_control_classic_data::on_acks()</span></div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span> </div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a79e85a67e583b74cc414524d53650892">  228</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a79e85a67e583b74cc414524d53650892">Congestion_control_classic_data::on_congestion_event</a>(<span class="keywordtype">size_t</span> new_slow_start_thresh_bytes,</div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span>                                                          <span class="keywordtype">size_t</span> new_cong_wnd_bytes)</div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span>{</div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span>  <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a092ddd8d1f700b426a5f9e0184af004f">log_state</a>(<span class="stringliteral">&quot;event-handling-before&quot;</span>);</div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span> </div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno">  233</span>  <span class="comment">/* They are updating CWND and/or SSTHRESH due to some (unspecified) event.  For example the</span></div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><span class="comment">   * classic Reno algorithm (more or less) halves CWND and sets SSTHRESH to this halved CWND,</span></div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span><span class="comment">   * whenever a non-timeout packet loss is detected.</span></div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="comment">   *</span></div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="comment">   * First figure out what to do about m_acked_bytes_since_window_update given this change. We may</span></div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno">  238</span><span class="comment">   * have to reset it to zero.  This is fairly important, as it basically resets the congestion</span></div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno">  239</span><span class="comment">   * avoidance state to that suitable to the beginning of the congestion avoidance phase (which may</span></div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span><span class="comment">   * then happen immediately or after one or more slow start phases, depending on the CWND vs.</span></div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span><span class="comment">   * SSTHRESH comparison).</span></div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span><span class="comment">   *</span></div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="comment">   * Let us consider the possibilities.  (It may help to draw a mental or physical graph of CWND and</span></div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno">  244</span><span class="comment">   * SSTHRESH over time.)  In slow start, where CWND &lt; SSTHRESH, CWND is increasing exponentially</span></div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno">  245</span><span class="comment">   * (for every incoming full acknowledgment), and m_acked_bytes_since_window_update is not used.</span></div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span><span class="comment">   * In congestion avoidance, where CWND &gt;= SSTHRESH, CWND is increasing linearly and</span></div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span><span class="comment">   * m_acked_bytes_since_window_update is used to keep track of this process.  Whenever congestion</span></div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span><span class="comment">   * avoidance ends (in favor of slow start or a different congestion avoidance phase at a lower [or</span></div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span><span class="comment">   * higher?] CWND), m_acked_bytes_since_window_update must be reset to 0.  So, the possibilities:</span></div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno">  250</span><span class="comment">   *</span></div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno">  251</span><span class="comment">   *   1. They&#39;re changing CWND (usually lower, e.g., Reno halves it).  This introduces</span></div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span><span class="comment">   *      &quot;discontinuity&quot; in the CWND value over time, so if any congestion avoidance phase was in</span></div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span><span class="comment">   *      progress, it is now over. Set to 0 to avoid affecting the next congestion avoidance phase</span></div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span><span class="comment">   *      (whether it happens now or after a slow start phase).  If no congestion avoidance phase</span></div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span><span class="comment">   *      was in progress, then it is already 0 and can be safely set to 0 again (or it can be left</span></div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span><span class="comment">   *      alone; makes no difference).</span></div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno">  257</span><span class="comment">   *</span></div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno">  258</span><span class="comment">   *   2. CWND is staying constant, but SSTHRESH is changing.  If we are in slow start, then we&#39;re</span></div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span><span class="comment">   *      not in congestion avoidance, so it is already set to 0 so no need to do anything.  If we</span></div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno">  260</span><span class="comment">   *      are not in slow start, then we are in congestion avoidance.  If we are in congestion</span></div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span><span class="comment">   *      avoidance, and under the new SSTHRESH we remain in congestion avoidance, then the</span></div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span><span class="comment">   *      in-progress congestion avoidance increase can continue undisturbed.  Finally, if we are in</span></div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span><span class="comment">   *      congestion avoidance, and the new SSTHRESH would put us into slow start, then this</span></div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span><span class="comment">   *      congestion avoidance session is over, and we must set to 0 (to avoid affecting the next</span></div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno">  265</span><span class="comment">   *      congestion avoidance phase, if there is one).</span></div>
<div class="line"><a id="l00266" name="l00266"></a><span class="lineno">  266</span><span class="comment">   *</span></div>
<div class="line"><a id="l00267" name="l00267"></a><span class="lineno">  267</span><span class="comment">   * Most of the above is uncontroversial and is consistent with various implementations of classic</span></div>
<div class="line"><a id="l00268" name="l00268"></a><span class="lineno">  268</span><span class="comment">   * TCP congestion control (Reno and off-shoots like Westwood+).  Certainly -1- is clear-cut.</span></div>
<div class="line"><a id="l00269" name="l00269"></a><span class="lineno">  269</span><span class="comment">   * -2- is generally atypical (usually SSTHRESH changes only when CWND changes), but let&#39;s consider</span></div>
<div class="line"><a id="l00270" name="l00270"></a><span class="lineno">  270</span><span class="comment">   * it.  If CWND stays constant, while SSTHRESH moves from at or below to above CWND, then even if</span></div>
<div class="line"><a id="l00271" name="l00271"></a><span class="lineno">  271</span><span class="comment">   * unlikely it clearly means congestion avoidance is over.  So that case is not controversial.</span></div>
<div class="line"><a id="l00272" name="l00272"></a><span class="lineno">  272</span><span class="comment">   * The remaining case is if SSTHRESH moves but stays below CWND and the decision to not touch</span></div>
<div class="line"><a id="l00273" name="l00273"></a><span class="lineno">  273</span><span class="comment">   * m_acked_bytes_since_window_update (i.e., let congestion avoidance continue).  I find this</span></div>
<div class="line"><a id="l00274" name="l00274"></a><span class="lineno">  274</span><span class="comment">   * decision acceptable &lt;comment cuts out&gt;.  @todo Where did the rest of the comment go?</span></div>
<div class="line"><a id="l00275" name="l00275"></a><span class="lineno">  275</span><span class="comment">   * why is the decision acceptable?  Didn&#39;t save? */</span></div>
<div class="line"><a id="l00276" name="l00276"></a><span class="lineno">  276</span>  <span class="keywordflow">if</span> ((new_cong_wnd_bytes != <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a>) <span class="comment">// Case 1 above.</span></div>
<div class="line"><a id="l00277" name="l00277"></a><span class="lineno">  277</span>      <span class="comment">// Case 2 above:</span></div>
<div class="line"><a id="l00278" name="l00278"></a><span class="lineno">  278</span>      || ((!<a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#aecb03f208c177ec3cbce5242f19efee0">in_slow_start</a>()) &amp;&amp; <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#aecb03f208c177ec3cbce5242f19efee0">in_slow_start</a>(new_slow_start_thresh_bytes, new_cong_wnd_bytes)))</div>
<div class="line"><a id="l00279" name="l00279"></a><span class="lineno">  279</span>  {</div>
<div class="line"><a id="l00280" name="l00280"></a><span class="lineno">  280</span>    <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a217f407429d1cf215177e3f49f86b6d6">m_acked_bytes_since_window_update</a> = 0;</div>
<div class="line"><a id="l00281" name="l00281"></a><span class="lineno">  281</span>  }</div>
<div class="line"><a id="l00282" name="l00282"></a><span class="lineno">  282</span> </div>
<div class="line"><a id="l00283" name="l00283"></a><span class="lineno">  283</span>  <span class="comment">// Now the easy part.</span></div>
<div class="line"><a id="l00284" name="l00284"></a><span class="lineno">  284</span>  <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a239c6315ca562c4e782431879f39c74d">m_slow_start_thresh_bytes</a> = new_slow_start_thresh_bytes;</div>
<div class="line"><a id="l00285" name="l00285"></a><span class="lineno">  285</span>  <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a> = new_cong_wnd_bytes;</div>
<div class="line"><a id="l00286" name="l00286"></a><span class="lineno">  286</span> </div>
<div class="line"><a id="l00287" name="l00287"></a><span class="lineno">  287</span>  <span class="comment">// In case they gave a too-high value for congestion window.  (SSTHRESH can be arbitrarily high.)</span></div>
<div class="line"><a id="l00288" name="l00288"></a><span class="lineno">  288</span>  <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7b798f3211fd2214477355b95e2d10d2">clamp_congestion_window</a>();</div>
<div class="line"><a id="l00289" name="l00289"></a><span class="lineno">  289</span> </div>
<div class="line"><a id="l00290" name="l00290"></a><span class="lineno">  290</span>  <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a092ddd8d1f700b426a5f9e0184af004f">log_state</a>(<span class="stringliteral">&quot;event-handling-after&quot;</span>);</div>
<div class="line"><a id="l00291" name="l00291"></a><span class="lineno">  291</span>} <span class="comment">// Congestion_control_classic_data::on_congestion_event()</span></div>
<div class="line"><a id="l00292" name="l00292"></a><span class="lineno">  292</span> </div>
<div class="line"><a id="l00293" name="l00293"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a63316b5d9e9a27816b09bb52c464b588">  293</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a63316b5d9e9a27816b09bb52c464b588">Congestion_control_classic_data::on_drop_timeout</a>(<span class="keywordtype">size_t</span> new_slow_start_thresh_bytes)</div>
<div class="line"><a id="l00294" name="l00294"></a><span class="lineno">  294</span>{</div>
<div class="line"><a id="l00295" name="l00295"></a><span class="lineno">  295</span>  <span class="keyword">using </span>std::max;</div>
<div class="line"><a id="l00296" name="l00296"></a><span class="lineno">  296</span> </div>
<div class="line"><a id="l00297" name="l00297"></a><span class="lineno">  297</span>  <span class="keyword">const</span> <a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> sock = <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">socket</a>();</div>
<div class="line"><a id="l00298" name="l00298"></a><span class="lineno">  298</span> </div>
<div class="line"><a id="l00299" name="l00299"></a><span class="lineno">  299</span>  <span class="comment">/* Node has detected a major loss event in the form of a Drop Timeout.  In most congestion</span></div>
<div class="line"><a id="l00300" name="l00300"></a><span class="lineno">  300</span><span class="comment">   * control algorithms this causes CWND to be decreased to a low value, as inspired by classic Reno</span></div>
<div class="line"><a id="l00301" name="l00301"></a><span class="lineno">  301</span><span class="comment">   * (RFC 5681).  On the other hand SSTHRESH is set to a strategy-dependent value, which is that&#39;s</span></div>
<div class="line"><a id="l00302" name="l00302"></a><span class="lineno">  302</span><span class="comment">   * given to us as an argument.  Certainly the specific strategy may also reset other state. */</span></div>
<div class="line"><a id="l00303" name="l00303"></a><span class="lineno">  303</span> </div>
<div class="line"><a id="l00304" name="l00304"></a><span class="lineno">  304</span>  <span class="comment">// RFC 5689-3.1 (set CWND to a low value; note: not the initial CWND, which can be higher).</span></div>
<div class="line"><a id="l00305" name="l00305"></a><span class="lineno">  305</span>  <span class="keyword">const</span> <span class="keywordtype">size_t</span> new_cong_wnd_bytes</div>
<div class="line"><a id="l00306" name="l00306"></a><span class="lineno">  306</span>    = sock-&gt;opt(sock-&gt;m_opts.m_st_cong_ctl_cong_wnd_on_drop_timeout_blocks) * sock-&gt;max_block_size();</div>
<div class="line"><a id="l00307" name="l00307"></a><span class="lineno">  307</span>  <span class="comment">// ^-- @todo Consistently with some other options, have value 0 mean &quot;use RFC value,&quot; which is 1.</span></div>
<div class="line"><a id="l00308" name="l00308"></a><span class="lineno">  308</span> </div>
<div class="line"><a id="l00309" name="l00309"></a><span class="lineno">  309</span>  <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a79e85a67e583b74cc414524d53650892">on_congestion_event</a>(new_slow_start_thresh_bytes, new_cong_wnd_bytes);</div>
<div class="line"><a id="l00310" name="l00310"></a><span class="lineno">  310</span>} <span class="comment">// Congestion_control_classic_data::on_drop_timeout()</span></div>
<div class="line"><a id="l00311" name="l00311"></a><span class="lineno">  311</span> </div>
<div class="line"><a id="l00312" name="l00312"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#afbe0609319f117e90074e1241abbba5c">  312</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#afbe0609319f117e90074e1241abbba5c">Congestion_control_classic_data::on_idle_timeout</a>()</div>
<div class="line"><a id="l00313" name="l00313"></a><span class="lineno">  313</span>{</div>
<div class="line"><a id="l00314" name="l00314"></a><span class="lineno">  314</span>  <span class="comment">/* Node has detected that nothing has been sent out by us for a while.  (Note that this is</span></div>
<div class="line"><a id="l00315" name="l00315"></a><span class="lineno">  315</span><span class="comment">   * different from a Drop Timeout.  A Drop Timeout causes data to be sent (either retransmitted [if</span></div>
<div class="line"><a id="l00316" name="l00316"></a><span class="lineno">  316</span><span class="comment">   * used] or new data), which resets the state back to non-idle for a while.)  Per TCP</span></div>
<div class="line"><a id="l00317" name="l00317"></a><span class="lineno">  317</span><span class="comment">   * RFC 5681 (and DCCP CCID 2 RFC 4341), in this case we are to simply set CWND back to its initial</span></div>
<div class="line"><a id="l00318" name="l00318"></a><span class="lineno">  318</span><span class="comment">   * value (unless that would increase it [e.g., if we had recently hit Drop Timeout as well], in</span></div>
<div class="line"><a id="l00319" name="l00319"></a><span class="lineno">  319</span><span class="comment">   * which case just leave it alone).  SSTHRESH is to be left alone.  Thus we will slow-start much</span></div>
<div class="line"><a id="l00320" name="l00320"></a><span class="lineno">  320</span><span class="comment">   * as we would at the beginning of the connection, except that SSTHRESH stays constant and is not</span></div>
<div class="line"><a id="l00321" name="l00321"></a><span class="lineno">  321</span><span class="comment">   * set back to infinity.</span></div>
<div class="line"><a id="l00322" name="l00322"></a><span class="lineno">  322</span><span class="comment">   *</span></div>
<div class="line"><a id="l00323" name="l00323"></a><span class="lineno">  323</span><span class="comment">   * There is at least one RFC with a more moderate policy, but it&#39;s not standard, and let&#39;s not</span></div>
<div class="line"><a id="l00324" name="l00324"></a><span class="lineno">  324</span><span class="comment">   * get into it for now.</span></div>
<div class="line"><a id="l00325" name="l00325"></a><span class="lineno">  325</span><span class="comment">   *</span></div>
<div class="line"><a id="l00326" name="l00326"></a><span class="lineno">  326</span><span class="comment">   * Certainly the specific strategy may also reset other state. */</span></div>
<div class="line"><a id="l00327" name="l00327"></a><span class="lineno">  327</span> </div>
<div class="line"><a id="l00328" name="l00328"></a><span class="lineno">  328</span>  <span class="keyword">const</span> <a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> sock = <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">socket</a>();</div>
<div class="line"><a id="l00329" name="l00329"></a><span class="lineno">  329</span>  <span class="keywordflow">if</span> (<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a> &lt;= <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7c792d850821c8a7c711204db867089b">m_init_cong_wnd_bytes</a>)</div>
<div class="line"><a id="l00330" name="l00330"></a><span class="lineno">  330</span>  {</div>
<div class="line"><a id="l00331" name="l00331"></a><span class="lineno">  331</span>    <a class="code hl_define" href="log_8hpp.html#affcf2e4c496ce3f42adf981669c623b8">FLOW_LOG_TRACE</a>(<span class="stringliteral">&quot;cong_ctl [&quot;</span> &lt;&lt; sock &lt;&lt; <span class="stringliteral">&quot;] update: Idle Timeout event; &quot;</span></div>
<div class="line"><a id="l00332" name="l00332"></a><span class="lineno">  332</span>                   <span class="stringliteral">&quot;cong_wnd [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a>) &lt;&lt; <span class="stringliteral">&quot;] is &quot;</span></div>
<div class="line"><a id="l00333" name="l00333"></a><span class="lineno">  333</span>                   <span class="stringliteral">&quot;already &lt;= initial cong_wnd [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7c792d850821c8a7c711204db867089b">m_init_cong_wnd_bytes</a>) &lt;&lt; <span class="stringliteral">&quot;].&quot;</span>);</div>
<div class="line"><a id="l00334" name="l00334"></a><span class="lineno">  334</span>  }</div>
<div class="line"><a id="l00335" name="l00335"></a><span class="lineno">  335</span>  <span class="keywordflow">else</span></div>
<div class="line"><a id="l00336" name="l00336"></a><span class="lineno">  336</span>  {</div>
<div class="line"><a id="l00337" name="l00337"></a><span class="lineno">  337</span>    <span class="comment">// Below call will log details.</span></div>
<div class="line"><a id="l00338" name="l00338"></a><span class="lineno">  338</span>    <a class="code hl_define" href="log_8hpp.html#affcf2e4c496ce3f42adf981669c623b8">FLOW_LOG_TRACE</a>(<span class="stringliteral">&quot;cong_ctl [&quot;</span> &lt;&lt; <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">socket</a>() &lt;&lt; <span class="stringliteral">&quot;] update: Idle Timeout event; set cong_wnd to initial cong_wnd.&quot;</span>);</div>
<div class="line"><a id="l00339" name="l00339"></a><span class="lineno">  339</span> </div>
<div class="line"><a id="l00340" name="l00340"></a><span class="lineno">  340</span>    <span class="comment">// Don&#39;t change SSTHRESH.</span></div>
<div class="line"><a id="l00341" name="l00341"></a><span class="lineno">  341</span>    <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a79e85a67e583b74cc414524d53650892">on_congestion_event</a>(<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a239c6315ca562c4e782431879f39c74d">m_slow_start_thresh_bytes</a>, <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7c792d850821c8a7c711204db867089b">m_init_cong_wnd_bytes</a>);</div>
<div class="line"><a id="l00342" name="l00342"></a><span class="lineno">  342</span>  }</div>
<div class="line"><a id="l00343" name="l00343"></a><span class="lineno">  343</span>} <span class="comment">// Congestion_control_classic_data::on_idle_timeout()</span></div>
<div class="line"><a id="l00344" name="l00344"></a><span class="lineno">  344</span> </div>
<div class="line"><a id="l00345" name="l00345"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a9c6cac4d5409855f5e39f4411d787ad9">  345</a></span><span class="keywordtype">bool</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a9c6cac4d5409855f5e39f4411d787ad9">Congestion_control_classic_data::congestion_window_at_limit</a>()<span class="keyword"> const</span></div>
<div class="line"><a id="l00346" name="l00346"></a><span class="lineno">  346</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00347" name="l00347"></a><span class="lineno">  347</span>  <span class="keyword">const</span> <a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> sock = <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">socket</a>();</div>
<div class="line"><a id="l00348" name="l00348"></a><span class="lineno">  348</span>  <span class="keywordflow">return</span> <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a></div>
<div class="line"><a id="l00349" name="l00349"></a><span class="lineno">  349</span>         &gt;= sock-&gt;opt(sock-&gt;m_opts.m_st_cong_ctl_max_cong_wnd_blocks) * sock-&gt;max_block_size();</div>
<div class="line"><a id="l00350" name="l00350"></a><span class="lineno">  350</span>}</div>
<div class="line"><a id="l00351" name="l00351"></a><span class="lineno">  351</span> </div>
<div class="line"><a id="l00352" name="l00352"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7b798f3211fd2214477355b95e2d10d2">  352</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7b798f3211fd2214477355b95e2d10d2">Congestion_control_classic_data::clamp_congestion_window</a>()</div>
<div class="line"><a id="l00353" name="l00353"></a><span class="lineno">  353</span>{</div>
<div class="line"><a id="l00354" name="l00354"></a><span class="lineno">  354</span>  <span class="keyword">const</span> <a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> sock = <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">socket</a>();</div>
<div class="line"><a id="l00355" name="l00355"></a><span class="lineno">  355</span>  <span class="keyword">const</span> <span class="keywordtype">size_t</span> limit = sock-&gt;opt(sock-&gt;m_opts.m_st_cong_ctl_max_cong_wnd_blocks) * sock-&gt;max_block_size();</div>
<div class="line"><a id="l00356" name="l00356"></a><span class="lineno">  356</span>  <span class="keywordflow">if</span> (<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a> &gt; limit)</div>
<div class="line"><a id="l00357" name="l00357"></a><span class="lineno">  357</span>  {</div>
<div class="line"><a id="l00358" name="l00358"></a><span class="lineno">  358</span>    <a class="code hl_define" href="log_8hpp.html#affcf2e4c496ce3f42adf981669c623b8">FLOW_LOG_TRACE</a>(<span class="stringliteral">&quot;cong_ctl [&quot;</span> &lt;&lt; sock &lt;&lt; <span class="stringliteral">&quot;] update: &quot;</span></div>
<div class="line"><a id="l00359" name="l00359"></a><span class="lineno">  359</span>                   <span class="stringliteral">&quot;clamping cong_wnd [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a>) &lt;&lt; <span class="stringliteral">&quot;] &quot;</span></div>
<div class="line"><a id="l00360" name="l00360"></a><span class="lineno">  360</span>                   <span class="stringliteral">&quot;to [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(limit) &lt;&lt; <span class="stringliteral">&quot;].&quot;</span>);</div>
<div class="line"><a id="l00361" name="l00361"></a><span class="lineno">  361</span>    <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a> = limit;</div>
<div class="line"><a id="l00362" name="l00362"></a><span class="lineno">  362</span>  }</div>
<div class="line"><a id="l00363" name="l00363"></a><span class="lineno">  363</span>}</div>
<div class="line"><a id="l00364" name="l00364"></a><span class="lineno">  364</span> </div>
<div class="line"><a id="l00365" name="l00365"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#aecb03f208c177ec3cbce5242f19efee0">  365</a></span><span class="keywordtype">bool</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#aecb03f208c177ec3cbce5242f19efee0">Congestion_control_classic_data::in_slow_start</a>()<span class="keyword"> const</span></div>
<div class="line"><a id="l00366" name="l00366"></a><span class="lineno">  366</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00367" name="l00367"></a><span class="lineno">  367</span>  <span class="keywordflow">return</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#aecb03f208c177ec3cbce5242f19efee0">in_slow_start</a>(<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a>, <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a239c6315ca562c4e782431879f39c74d">m_slow_start_thresh_bytes</a>);</div>
<div class="line"><a id="l00368" name="l00368"></a><span class="lineno">  368</span>}</div>
<div class="line"><a id="l00369" name="l00369"></a><span class="lineno">  369</span> </div>
<div class="line"><a id="l00370" name="l00370"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a1468dbf1d36eff05d61657f46df8489b">  370</a></span><span class="keywordtype">bool</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#aecb03f208c177ec3cbce5242f19efee0">Congestion_control_classic_data::in_slow_start</a>(<span class="keywordtype">size_t</span> cong_wnd_bytes, <span class="keywordtype">size_t</span> slow_start_thresh_bytes) <span class="comment">// Static.</span></div>
<div class="line"><a id="l00371" name="l00371"></a><span class="lineno">  371</span>{</div>
<div class="line"><a id="l00372" name="l00372"></a><span class="lineno">  372</span>  <span class="keywordflow">return</span> cong_wnd_bytes &lt; slow_start_thresh_bytes;</div>
<div class="line"><a id="l00373" name="l00373"></a><span class="lineno">  373</span>}</div>
<div class="line"><a id="l00374" name="l00374"></a><span class="lineno">  374</span> </div>
<div class="line"><a id="l00375" name="l00375"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a092ddd8d1f700b426a5f9e0184af004f">  375</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a092ddd8d1f700b426a5f9e0184af004f">Congestion_control_classic_data::log_state</a>(<span class="keyword">const</span> std::string&amp; context)<span class="keyword"> const</span></div>
<div class="line"><a id="l00376" name="l00376"></a><span class="lineno">  376</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00377" name="l00377"></a><span class="lineno">  377</span>  <span class="keyword">using </span>std::numeric_limits;</div>
<div class="line"><a id="l00378" name="l00378"></a><span class="lineno">  378</span> </div>
<div class="line"><a id="l00379" name="l00379"></a><span class="lineno">  379</span>  <span class="keyword">const</span> <a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> sock = <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">socket</a>();</div>
<div class="line"><a id="l00380" name="l00380"></a><span class="lineno">  380</span>  <a class="code hl_define" href="log_8hpp.html#affcf2e4c496ce3f42adf981669c623b8">FLOW_LOG_TRACE</a>(<span class="stringliteral">&quot;cong_ctl [&quot;</span> &lt;&lt; sock &lt;&lt; <span class="stringliteral">&quot;] info [&quot;</span> &lt;&lt; context &lt;&lt;</div>
<div class="line"><a id="l00381" name="l00381"></a><span class="lineno">  381</span>                 <span class="charliteral">&#39;|&#39;</span> &lt;&lt; (<a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#aecb03f208c177ec3cbce5242f19efee0">in_slow_start</a>() ? <span class="stringliteral">&quot;slow_start&quot;</span> : <span class="stringliteral">&quot;cong_avoid&quot;</span>) &lt;&lt; <span class="stringliteral">&quot;]: &quot;</span></div>
<div class="line"><a id="l00382" name="l00382"></a><span class="lineno">  382</span>                 <span class="stringliteral">&quot;cong_wnd [&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">m_cong_wnd_bytes</a>) &lt;&lt; <span class="stringliteral">&quot;]; &quot;</span></div>
<div class="line"><a id="l00383" name="l00383"></a><span class="lineno">  383</span>                 <span class="stringliteral">&quot;sl_st_thresh &quot;</span></div>
<div class="line"><a id="l00384" name="l00384"></a><span class="lineno">  384</span>                 <span class="stringliteral">&quot;[&quot;</span> &lt;&lt; ((<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a239c6315ca562c4e782431879f39c74d">m_slow_start_thresh_bytes</a> == numeric_limits&lt;size_t&gt;::max())</div>
<div class="line"><a id="l00385" name="l00385"></a><span class="lineno">  385</span>                           ? <span class="stringliteral">&quot;inf&quot;</span> : sock-&gt;bytes_blocks_str(<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a239c6315ca562c4e782431879f39c74d">m_slow_start_thresh_bytes</a>)) &lt;&lt; <span class="stringliteral">&quot;] &quot;</span></div>
<div class="line"><a id="l00386" name="l00386"></a><span class="lineno">  386</span>                 <span class="stringliteral">&quot;cong_avoid_acked &quot;</span></div>
<div class="line"><a id="l00387" name="l00387"></a><span class="lineno">  387</span>                 <span class="stringliteral">&quot;[&quot;</span> &lt;&lt; sock-&gt;bytes_blocks_str(<a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a217f407429d1cf215177e3f49f86b6d6">m_acked_bytes_since_window_update</a>) &lt;&lt; <span class="stringliteral">&quot;].&quot;</span>);</div>
<div class="line"><a id="l00388" name="l00388"></a><span class="lineno">  388</span>}</div>
<div class="line"><a id="l00389" name="l00389"></a><span class="lineno">  389</span> </div>
<div class="line"><a id="l00390" name="l00390"></a><span class="lineno"><a class="line" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">  390</a></span><a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> <a class="code hl_function" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">Congestion_control_classic_data::socket</a>()<span class="keyword"> const</span></div>
<div class="line"><a id="l00391" name="l00391"></a><span class="lineno">  391</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00392" name="l00392"></a><span class="lineno">  392</span>  <span class="keyword">const</span> <a class="code hl_typedef" href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">Peer_socket::Const_ptr</a> sock = <a class="code hl_variable" href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#ae8b85cd84e7e0496ad10814008fbd9fc">m_sock</a>.lock();</div>
<div class="line"><a id="l00393" name="l00393"></a><span class="lineno">  393</span>  assert(sock);</div>
<div class="line"><a id="l00394" name="l00394"></a><span class="lineno">  394</span>  <span class="keywordflow">return</span> sock;</div>
<div class="line"><a id="l00395" name="l00395"></a><span class="lineno">  395</span>}</div>
<div class="line"><a id="l00396" name="l00396"></a><span class="lineno">  396</span> </div>
<div class="line"><a id="l00397" name="l00397"></a><span class="lineno">  397</span>} <span class="comment">// namespace flow::net_flow</span></div>
<div class="ttc" id="aclassflow_1_1log_1_1Logger_html"><div class="ttname"><a href="classflow_1_1log_1_1Logger.html">flow::log::Logger</a></div><div class="ttdoc">Interface that the user should implement, passing the implementing Logger into logging classes (Flow'...</div><div class="ttdef"><b>Definition:</b> <a href="log_8hpp_source.html#l01280">log.hpp:1284</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a092ddd8d1f700b426a5f9e0184af004f"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a092ddd8d1f700b426a5f9e0184af004f">flow::net_flow::Congestion_control_classic_data::log_state</a></div><div class="ttdeci">void log_state(const std::string &amp;context) const</div><div class="ttdoc">Logs, in a TRACE message, all internal state values.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00375">cong_ctl_util.cpp:375</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a1ca80ab86d6289af0f3b2bf123edd627"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a1ca80ab86d6289af0f3b2bf123edd627">flow::net_flow::Congestion_control_classic_data::slow_start_threshold_bytes</a></div><div class="ttdeci">size_t slow_start_threshold_bytes() const</div><div class="ttdoc">Return current stored SSTHRESH value in bytes.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00071">cong_ctl_util.cpp:71</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a217f407429d1cf215177e3f49f86b6d6"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a217f407429d1cf215177e3f49f86b6d6">flow::net_flow::Congestion_control_classic_data::m_acked_bytes_since_window_update</a></div><div class="ttdeci">size_t m_acked_bytes_since_window_update</div><div class="ttdoc">While in congestion avoidance mode (!in_slow_start()), the # of acked bytes reported to on_acks() tha...</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8hpp_source.html#l00277">cong_ctl_util.hpp:277</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a239c6315ca562c4e782431879f39c74d"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a239c6315ca562c4e782431879f39c74d">flow::net_flow::Congestion_control_classic_data::m_slow_start_thresh_bytes</a></div><div class="ttdeci">size_t m_slow_start_thresh_bytes</div><div class="ttdoc">Current value of SSTRESH.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8hpp_source.html#l00261">cong_ctl_util.hpp:261</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a2eb9570b7c5e58a732b05a19187c0fef"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a2eb9570b7c5e58a732b05a19187c0fef">flow::net_flow::Congestion_control_classic_data::m_cong_wnd_bytes</a></div><div class="ttdeci">size_t m_cong_wnd_bytes</div><div class="ttdoc">Current value of CWND.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8hpp_source.html#l00255">cong_ctl_util.hpp:255</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a537fe6cb424b4e2591cc4673ed9ec8a1"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a537fe6cb424b4e2591cc4673ed9ec8a1">flow::net_flow::Congestion_control_classic_data::Congestion_control_classic_data</a></div><div class="ttdeci">Congestion_control_classic_data(log::Logger *logger_ptr, Peer_socket::Const_ptr sock)</div><div class="ttdoc">Constructs object by setting up logging and saving a pointer to the containing Peer_socket,...</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00033">cong_ctl_util.cpp:33</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a63316b5d9e9a27816b09bb52c464b588"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a63316b5d9e9a27816b09bb52c464b588">flow::net_flow::Congestion_control_classic_data::on_drop_timeout</a></div><div class="ttdeci">void on_drop_timeout(size_t new_slow_start_thresh_bytes)</div><div class="ttdoc">Adjust state, including CWND and SSTHRESH, assuming a Drop Timeout just occurred.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00293">cong_ctl_util.cpp:293</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a79e85a67e583b74cc414524d53650892"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a79e85a67e583b74cc414524d53650892">flow::net_flow::Congestion_control_classic_data::on_congestion_event</a></div><div class="ttdeci">void on_congestion_event(size_t new_slow_start_thresh_bytes, size_t new_cong_wnd_bytes)</div><div class="ttdoc">Sets internally stored SSHTRESH and CWND to the given values; appropriately resets internal state so ...</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00228">cong_ctl_util.cpp:228</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a7b798f3211fd2214477355b95e2d10d2"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7b798f3211fd2214477355b95e2d10d2">flow::net_flow::Congestion_control_classic_data::clamp_congestion_window</a></div><div class="ttdeci">void clamp_congestion_window()</div><div class="ttdoc">If congestion_window_at_limit(), sets CWND to the limit value.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00352">cong_ctl_util.cpp:352</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a7c792d850821c8a7c711204db867089b"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a7c792d850821c8a7c711204db867089b">flow::net_flow::Congestion_control_classic_data::m_init_cong_wnd_bytes</a></div><div class="ttdeci">const size_t m_init_cong_wnd_bytes</div><div class="ttdoc">Initial value of CWND in constructor.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8hpp_source.html#l00258">cong_ctl_util.hpp:258</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a842fd11c65c3be53ce3d81a7f050f7d7"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a842fd11c65c3be53ce3d81a7f050f7d7">flow::net_flow::Congestion_control_classic_data::socket</a></div><div class="ttdeci">Peer_socket::Const_ptr socket() const</div><div class="ttdoc">Analogous to Congestion_control_strategy::socket().</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00390">cong_ctl_util.cpp:390</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_a9c6cac4d5409855f5e39f4411d787ad9"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#a9c6cac4d5409855f5e39f4411d787ad9">flow::net_flow::Congestion_control_classic_data::congestion_window_at_limit</a></div><div class="ttdeci">bool congestion_window_at_limit() const</div><div class="ttdoc">Returns true if and only if the stored CWND is &gt;= a certain constant maximum value.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00345">cong_ctl_util.cpp:345</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_ab3e34468efdf4d9e5b29eceb1fe84665"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#ab3e34468efdf4d9e5b29eceb1fe84665">flow::net_flow::Congestion_control_classic_data::on_acks</a></div><div class="ttdeci">void on_acks(size_t bytes)</div><div class="ttdoc">Adjusts state, including potentially CWND, based on either &quot;congestion avoidance&quot; or &quot;slow start&quot; alg...</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00076">cong_ctl_util.cpp:76</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_acaa476e1821e7ed1344de8c5bfc0c9a7"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#acaa476e1821e7ed1344de8c5bfc0c9a7">flow::net_flow::Congestion_control_classic_data::init_congestion_window_bytes</a></div><div class="ttdeci">size_t init_congestion_window_bytes() const</div><div class="ttdoc">The value to which the constructor set the stored CWND value (also known as Initial Window or IW).</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00066">cong_ctl_util.cpp:66</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_ad5141d276b63528195d360f537cd4882"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#ad5141d276b63528195d360f537cd4882">flow::net_flow::Congestion_control_classic_data::S_MAX_SLOW_START_CWND_INCREMENT_BLOCKS</a></div><div class="ttdeci">static const size_t S_MAX_SLOW_START_CWND_INCREMENT_BLOCKS</div><div class="ttdoc">The constant that limits how much CWND can grow in slow start for a single ack group.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8hpp_source.html#l00247">cong_ctl_util.hpp:247</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_adbda0ed3747b1eea62f4d790c37dbe46"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#adbda0ed3747b1eea62f4d790c37dbe46">flow::net_flow::Congestion_control_classic_data::congestion_window_bytes</a></div><div class="ttdeci">size_t congestion_window_bytes() const</div><div class="ttdoc">Return current stored CWND value in bytes.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00061">cong_ctl_util.cpp:61</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_ae8b85cd84e7e0496ad10814008fbd9fc"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#ae8b85cd84e7e0496ad10814008fbd9fc">flow::net_flow::Congestion_control_classic_data::m_sock</a></div><div class="ttdeci">boost::weak_ptr&lt; Peer_socket::Const_ptr::element_type &gt; m_sock</div><div class="ttdoc">Same meaning as in Congestion_control_strategy.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8hpp_source.html#l00252">cong_ctl_util.hpp:252</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_aecb03f208c177ec3cbce5242f19efee0"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#aecb03f208c177ec3cbce5242f19efee0">flow::net_flow::Congestion_control_classic_data::in_slow_start</a></div><div class="ttdeci">bool in_slow_start() const</div><div class="ttdoc">Return true if and only if CWND &lt; SSTHRESH.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00365">cong_ctl_util.cpp:365</a></div></div>
<div class="ttc" id="aclassflow_1_1net__flow_1_1Congestion__control__classic__data_html_afbe0609319f117e90074e1241abbba5c"><div class="ttname"><a href="classflow_1_1net__flow_1_1Congestion__control__classic__data.html#afbe0609319f117e90074e1241abbba5c">flow::net_flow::Congestion_control_classic_data::on_idle_timeout</a></div><div class="ttdeci">void on_idle_timeout()</div><div class="ttdoc">Adjust state, namely CWND, assuming an Idle Timeout just occurred.</div><div class="ttdef"><b>Definition:</b> <a href="cong__ctl__util_8cpp_source.html#l00312">cong_ctl_util.cpp:312</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Shared__ptr__alias__holder_html_aef7998db71c60eeb5d1e3d1a97c14886"><div class="ttname"><a href="classflow_1_1util_1_1Shared__ptr__alias__holder.html#aef7998db71c60eeb5d1e3d1a97c14886">flow::util::Shared_ptr_alias_holder&lt; boost::shared_ptr&lt; Peer_socket &gt; &gt;::Const_ptr</a></div><div class="ttdeci">Const_target_ptr Const_ptr</div><div class="ttdoc">Short-hand for ref-counted pointer to immutable values of type Target_type::element_type (a-la T cons...</div><div class="ttdef"><b>Definition:</b> <a href="shared__ptr__alias__holder_8hpp_source.html#l00127">shared_ptr_alias_holder.hpp:127</a></div></div>
<div class="ttc" id="acong__ctl__util_8hpp_html"><div class="ttname"><a href="cong__ctl__util_8hpp.html">cong_ctl_util.hpp</a></div></div>
<div class="ttc" id="alog_8hpp_html_a325fdd4b5cf0be49b37d3b7b7c29070d"><div class="ttname"><a href="log_8hpp.html#a325fdd4b5cf0be49b37d3b7b7c29070d">FLOW_LOG_INFO</a></div><div class="ttdeci">#define FLOW_LOG_INFO(ARG_stream_fragment)</div><div class="ttdoc">Logs an INFO message into flow::log::Logger *get_logger() with flow::log::Component get_log_component...</div><div class="ttdef"><b>Definition:</b> <a href="log_8hpp_source.html#l00197">log.hpp:197</a></div></div>
<div class="ttc" id="alog_8hpp_html_affcf2e4c496ce3f42adf981669c623b8"><div class="ttname"><a href="log_8hpp.html#affcf2e4c496ce3f42adf981669c623b8">FLOW_LOG_TRACE</a></div><div class="ttdeci">#define FLOW_LOG_TRACE(ARG_stream_fragment)</div><div class="ttdoc">Logs a TRACE message into flow::log::Logger *get_logger() with flow::log::Component get_log_component...</div><div class="ttdef"><b>Definition:</b> <a href="log_8hpp_source.html#l00227">log.hpp:227</a></div></div>
<div class="ttc" id="anamespaceflow_1_1net__flow_html"><div class="ttname"><a href="namespaceflow_1_1net__flow.html">flow::net_flow</a></div><div class="ttdoc">Flow module containing the API and implementation of the Flow network protocol, a TCP-inspired stream...</div><div class="ttdef"><b>Definition:</b> <a href="asio_2node_8cpp_source.html#l00024">node.cpp:25</a></div></div>
<div class="ttc" id="anamespaceflow_html_a3938730ab4b89daf13d027a5f620e7ce"><div class="ttname"><a href="namespaceflow.html#a3938730ab4b89daf13d027a5f620e7ce">flow::Flow_log_component</a></div><div class="ttdeci">Flow_log_component</div><div class="ttdoc">The flow::log::Component payload enumeration comprising various log components used by Flow's own int...</div><div class="ttdef"><b>Definition:</b> <a href="common_8hpp_source.html#l00637">common.hpp:638</a></div></div>
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